* to return a proper ListenableFuture instead of using listenInPoolThread.
                 */
                getUninterruptibly(delegate);
              } catch (Throwable t) {
                // (including CancellationException and sneaky checked exception)
                // The task is presumably done, run the listeners.

            } else if (logger.isInfoEnabled()) {
                logger.info("Crawler is stopped.");
            }
            exitCode = Constants.EXIT_FAIL;
        } catch (final Throwable t) {
            logger.error("Crawler does not work correctly.", t);
            exitCode = Constants.EXIT_FAIL;
        } finally {
            if (commandThread != null && commandThread.isAlive()) {

            } else if (logger.isInfoEnabled()) {
                logger.info("ThumbnailGenerator is stopped.");
            }
            exitCode = Constants.EXIT_FAIL;
        } catch (final Throwable t) {
            logger.error("ThumbnailGenerator does not work correctly.", t);
            exitCode = Constants.EXIT_FAIL;
        } finally {
            if (systemMonitorTask != null) {

                default:
                    logger.error("Unknown thumbnail result: {} -> {}", thumbnailId, responseData.getUrl());
                    break;
                }
            } catch (final Throwable t) {
                logger.warn("Failed to create thumbnail: {} -> {} ({}:{})", thumbnailId, responseData.getUrl(),
                        t.getClass().getCanonicalName(), t.getMessage());

            }
            writeJsonResponse(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, e);
        }
    }

    protected String detailedMessage(final Throwable t) {
        if (t == null) {
            return "Unknown";
        }
        Throwable target = t;
        if (target.getCause() == null) {
            return target.getClass().getSimpleName() + "[" + target.getMessage() + "]";
        }

        }
      };

  private static final UncaughtExceptionHandler UNCAUGHT_EXCEPTION_HANDLER =
      new UncaughtExceptionHandler() {
        @Override
        public void uncaughtException(Thread t, Throwable e) {
          // No-op
        }
      };

  private ThreadFactoryBuilder builder;
  private volatile boolean completed = false;

  @Override
  public void setUp() {

      V value, @Nullable Exception except, CountDownLatch waitOn);

  /** Tests that the {@link Future#get()} method blocks until a value is available. */
  public void testGetBlocksUntilValueAvailable() throws Throwable {

    assertFalse(future.isDone());
    assertFalse(future.isCancelled());

    ExecutorService executor = Executors.newSingleThreadExecutor();

    try {

      sneakyThrow(exception);
    }
  }

  /** Throws an undeclared checked exception. */
  private static void sneakyThrow(Throwable t) {
    class SneakyThrower<T extends Throwable> {
      @SuppressWarnings("unchecked") // not really safe, but that's the point
      void throwIt(Throwable t) throws T {
        throw (T) t;
      }
    }
    new SneakyThrower<Error>().throwIt(t);
  }

  /**

        }
    }


    /**
     * {@inheritDoc}
     *
     * @see java.lang.Object#finalize()
     */
    @Override
    protected void finalize () throws Throwable {
        if ( this.usageCount.get() != 0 && this.open ) {
            log.warn("File handle was not properly closed: " + this);
            if ( this.creationBacktrace != null ) {

        }
    }


    /**
     * {@inheritDoc}
     *
     * @see java.lang.Object#finalize()
     */
    @Override
    protected void finalize () throws Throwable {
        if ( this.usageCount.get() != 0 ) {
            log.warn("Tree handle was not properly released " + this.resourceLoc.getURL());
        }
    }


    /**
     * {@inheritDoc}
     *